All modern ammo is waterproof - just ask spear fishermen who use powerheads. The only issue is that if the rounds are allowed to stay wet for a long period of time then you could get corrosion around the primer pockets (much more of a problem with salt water than fresh water). Just dry your ammo out at the end of the day and you'll be fine.

Cool, learned something today. Time to go home.

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Know the status of your weapon
Keep your muzzle oriented so that no one will be hurt if the firearm discharges
Keep your finger off the trigger until you have an adequate sight picture
Maintain situational awareness